The LR 4 beta just dropped, and I gotta say: it's fucking amazing.
A lot of bullshit features I wouldn't use, like Soft proofing, video support (although some of you might use this), maps, books and all that kinda shit.
There's been some other changes though that are friggin' awesome.
Personally I'm super stoked on RGB curves (yeaaaah!!!) and the new 'Basic panel', which has been revamped and has some new, less confusing, super powerful features.
Instead of the traditional recovery, fill light we now have: highlights, shadows, whites and blacks, which give you much more control and they're super powerful tools as well.
See for yourself here:
http://labs.adobe.com/technologies/lightroom4/ 